var isNav4 = false, isNav5 = false, isIE4 = false;
var strSeperator = "/"; 
// If you are using any Java validation on the back side you will want to use the / because 
// Java date validations do not recognize the dash as a valid date separator.
var vDateType = 3; // Global value for type of date format
//                1 = mm/dd/yyyy
//                2 = yyyy/dd/mm  (Unable to do date check at this time)
//                3 = dd/mm/yyyy
var vYearType = 4; //Set to 2 or 4 for number of digits in the year for Netscape
var vYearLength = 2; // Set to 4 if you want to force the user to enter 4 digits for the year before validating.
var err = 0; // Set the error code to a default of zero
if(navigator.appName == "Netscape") {
	if (navigator.appVersion < "5") {
		isNav4 = true;
		isNav5 = false;
	} else if (navigator.appVersion > "4") {
		isNav4 = false;
		isNav5 = true;
   }
} else {
	isIE4 = true;
}

	function DateFormat(vDateName, vDateValue, e, dateCheck, dateType) {
		vDateType = dateType;
		// vDateName = object name
		// vDateValue = value in the field being checked
		// e = event
		// dateCheck 
		// True  = Verify that the vDateValue is a valid date
		// False = Format values being entered into vDateValue only
		// vDateType
		// 1 = mm/dd/yyyy
		// 2 = yyyy/mm/dd
		// 3 = dd/mm/yyyy
		//Enter a tilde sign for the first number and you can check the variable information.
		if (vDateValue == "~") {
			alert("AppVersion = "+navigator.appVersion+" \nNav. 4 Version = "+isNav4+" \nNav. 5 Version = "+isNav5+" \nIE Version = "+isIE4+" \nYear Type = "+vYearType+" \nDate Type = "+vDateType+" \nSeparator = "+strSeperator);
			vDateName.value = "";
			vDateName.focus();
			return true;
		}
	
		var whichCode = (window.Event) ? e.which : e.keyCode;
		// Check to see if a seperator is already present.
		// bypass the date if a seperator is present and the length greater than 8
		if (vDateValue.length > 8 && isNav4) {
			if ((vDateValue.indexOf("-") >= 1) || (vDateValue.indexOf("/") >= 1))
				return true;
		}
		
		//Eliminate all the ASCII codes that are not valid
		var alphaCheck = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/-";
		if (alphaCheck.indexOf(vDateValue) >= 1) {
			if (isNav4) {
				vDateName.value = "";
				vDateName.focus();
				vDateName.select();
				return false;
			} else {
				vDateName.value = vDateName.value.substr(0, (vDateValue.length-1));
				return false;
		   }
		}
		if (whichCode == 8) { //Ignore the Netscape value for backspace. IE has no value
			return false;
		} else {
			//Create numeric string values for 0123456789/
			//The codes provided include both keyboard and keypad values
			var strCheck = '47,48,49,50,51,52,53,54,55,56,57,58,59,95,96,97,98,99,100,101,102,103,104,105';
			if (strCheck.indexOf(whichCode) != -1) {
				if (isNav4) {
					if (((vDateValue.length < 6 && dateCheck) || (vDateValue.length == 7 && dateCheck)) && (vDateValue.length >=1)) {
						alert("Invalid Date\nPlease Re-Enter");
						vDateName.value = "";
						vDateName.focus();
						vDateName.select();
						return false;
					}
					if (vDateValue.length == 6 && dateCheck) {
						var mDay = vDateName.value.substr(2,2);
						var mMonth = vDateName.value.substr(0,2);
						var mYear = vDateName.value.substr(4,4);
						//Turn a two digit year into a 4 digit year
						if (mYear.length == 2 && vYearType == 4) {
							var mToday = new Date();
							//If the year is greater than 30 years from now use 19, otherwise use 20
							var checkYear = mToday.getFullYear() + 30; 
							var mCheckYear = '20' + mYear;
							if (mCheckYear >= checkYear)
								mYear = '19' + mYear;
							else
								mYear = '20' + mYear;
						}
						var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
						if (!dateValid(vDateValueCheck)) {
							alert("Invalid Date\nPlease Re-Enter");
							vDateName.value = "";
							vDateName.focus();
							vDateName.select();
							return false;
						}
						return true;
					} else {
						// Reformat the date for validation and set date type to a 1
						if (vDateValue.length >= 8  && dateCheck) {
							if (vDateType == 1) {// mmddyyyy	
								var mDay = vDateName.value.substr(2,2);
								var mMonth = vDateName.value.substr(0,2);
								var mYear = vDateName.value.substr(4,4);
								vDateName.value = mMonth+strSeperator+mDay+strSeperator+mYear;
							}
							if (vDateType == 2) {// yyyymmdd
								var mYear = vDateName.value.substr(0,4);
								var mMonth = vDateName.value.substr(4,2);
								var mDay = vDateName.value.substr(6,2);
								vDateName.value = mYear+strSeperator+mMonth+strSeperator+mDay;
							}
							if (vDateType == 3) { // ddmmyyyy
								var mMonth = vDateName.value.substr(2,2);
								var mDay = vDateName.value.substr(0,2);
								var mYear = vDateName.value.substr(4,4);
								vDateName.value = mDay+strSeperator+mMonth+strSeperator+mYear;
							}
							//Create a temporary variable for storing the DateType and change
							//the DateType to a 1 for validation.
							var vDateTypeTemp = vDateType;
							vDateType = 1;
							var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
							if (!dateValid(vDateValueCheck)) {
								alert("Invalid Date\nPlease Re-Enter");
								vDateType = vDateTypeTemp;
								vDateName.value = "";
								vDateName.focus();
								vDateName.select();
								return false;
							}
						vDateType = vDateTypeTemp;
						return true;	
					} else {
						if (((vDateValue.length < 8 && dateCheck) || (vDateValue.length == 9 && dateCheck)) && (vDateValue.length >=1)) {
							alert("Invalid Date\nPlease Re-Enter");
							vDateName.value = "";
							vDateName.focus();
							vDateName.select();
							return false;
		         		}
		      		}
		   		}
		} else {
			// Non isNav Check
			if (((vDateValue.length < 8 && dateCheck) || (vDateValue.length == 9 && dateCheck)) && (vDateValue.length >=1)) {
				alert("Invalid Date\nPlease Re-Enter");
				vDateName.value = "";
				vDateName.focus();
				return true;
			}
			// Reformat date to format that can be validated. mm/dd/yyyy
			if (vDateValue.length >= 8 && dateCheck) {
			// Additional date formats can be entered here and parsed out to
			// a valid date format that the validation routine will recognize.
			if (vDateType == 1) { // mm/dd/yyyy
				var mMonth = vDateName.value.substr(0,2);
				var mDay = vDateName.value.substr(3,2);
				var mYear = vDateName.value.substr(6,4);
			}
			if (vDateType == 2) {// yyyy/mm/dd
				var mYear = vDateName.value.substr(0,4);
				var mMonth = vDateName.value.substr(5,2);
				var mDay = vDateName.value.substr(8,2);
			}
			if (vDateType == 3) { // dd/mm/yyyy
				var mDay = vDateName.value.substr(0,2);
				var mMonth = vDateName.value.substr(3,2);
				var mYear = vDateName.value.substr(6,4);
			}
			if (vYearLength == 4) {
				if (mYear.length < 4) {
					alert("Invalid Date\nPlease Re-Enter");
					vDateName.value = "";
					vDateName.focus();
					return true;
			   }
			}
			// Create temp. variable for storing the current vDateType
			var vDateTypeTemp = vDateType;
			// Change vDateType to a 1 for standard date format for validation
			// Type will be changed back when validation is completed.
			vDateType = 1;
			// Store reformatted date to new variable for validation.
			var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
			if (mYear.length == 2 && vYearType == 4 && dateCheck) {
				//Turn a two digit year into a 4 digit year
				var mToday = new Date();
				//If the year is greater than 30 years from now use 19, otherwise use 20
				var checkYear = mToday.getFullYear() + 30; 
				var mCheckYear = '20' + mYear;
				if (mCheckYear >= checkYear)
					mYear = '19' + mYear;
				else
					mYear = '20' + mYear;
				vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
				// Store the new value back to the field.  This function will
				// not work with date type of 2 since the year is entered first.
				if (vDateTypeTemp == 1) // mm/dd/yyyy
					vDateName.value = mMonth+strSeperator+mDay+strSeperator+mYear;
				if (vDateTypeTemp == 3) // dd/mm/yyyy
					vDateName.value = mDay+strSeperator+mMonth+strSeperator+mYear;
			} 
			if (!dateValid(vDateValueCheck)) {
				alert("Invalid Date\nPlease Re-Enter");
				vDateType = vDateTypeTemp;
				vDateName.value = "";
				vDateName.focus();
				return true;
			}
			vDateType = vDateTypeTemp;
			return true;
			} else {
				if (vDateType == 1) {
					if (vDateValue.length == 2) {
						vDateName.value = vDateValue+strSeperator;
					}
					if (vDateValue.length == 5) {
						vDateName.value = vDateValue+strSeperator;
			   		}
				}
				if (vDateType == 2) {
					if (vDateValue.length == 4) {
						vDateName.value = vDateValue+strSeperator;
					}
					if (vDateValue.length == 7) {
						vDateName.value = vDateValue+strSeperator;
			   		}
				} 
				if (vDateType == 3) {
					if (vDateValue.length == 2) {
						vDateName.value = vDateValue+strSeperator;
					}
					if (vDateValue.length == 5) {
						vDateName.value = vDateValue+strSeperator;
			   		}
				}
					return true;
			}
		}
		if (vDateValue.length == 10&& dateCheck) {
			if (!dateValid(vDateName)) {
				// Un-comment the next line of code for debugging the dateValid() function error messages
				//alert(err);  
				alert("Invalid Date\nPlease Re-Enter");
				vDateName.focus();
				vDateName.select();
			}
		}
		return false;
		} else {
				// If the value is not in the string return the string minus the last
				// key entered.
				if (isNav4) {
				vDateName.value = "";
				vDateName.focus();
				vDateName.select();
				return false;
				} else {
						vDateName.value = vDateName.value.substr(0, (vDateValue.length-1));
						return false;
				       }
			    }
		}
	}
	
	function dateValid(objName) {
		var strDate;
		var strDateArray;
		var strDay;
		var strMonth;
		var strYear;
		var intday;
		var intMonth;
		var intYear;
		var booFound = false;
		var datefield = objName;
		var strSeparatorArray = new Array("-"," ","/",".");
		var intElementNr;
		// var err = 0;
		var strMonthArray = new Array(12);
		strMonthArray[0] = "Jan";
		strMonthArray[1] = "Feb";
		strMonthArray[2] = "Mar";
		strMonthArray[3] = "Apr";
		strMonthArray[4] = "May";
		strMonthArray[5] = "Jun";
		strMonthArray[6] = "Jul";
		strMonthArray[7] = "Aug";
		strMonthArray[8] = "Sep";
		strMonthArray[9] = "Oct";
		strMonthArray[10] = "Nov";
		strMonthArray[11] = "Dec";
		//strDate = datefield.value;
		strDate = objName;
		if (strDate.length < 1) {
			return true;
		}
		for (intElementNr = 0; intElementNr < strSeparatorArray.length; intElementNr++) {
			if (strDate.indexOf(strSeparatorArray[intElementNr]) != -1) {
				strDateArray = strDate.split(strSeparatorArray[intElementNr]);
				if (strDateArray.length != 3) {
					err = 1;
					return false;
				} else {
					strDay = strDateArray[0];
					strMonth = strDateArray[1];
					strYear = strDateArray[2];
				}
				booFound = true;
			}
		}
		if (booFound == false) {
			if (strDate.length>5) {
				strDay = strDate.substr(0, 2);
				strMonth = strDate.substr(2, 2);
				strYear = strDate.substr(4);
		   	}
		}
		//Adjustment for short years entered
		if (strYear.length == 2) {
			strYear = '20' + strYear;
		}
		strTemp = strDay;
		strDay = strMonth;
		strMonth = strTemp;
		intday = parseInt(strDay, 10);
		if (isNaN(intday)) {
			err = 2;
			return false;
		}
		intMonth = parseInt(strMonth, 10);
		if (isNaN(intMonth)) {
			for (i = 0;i<12;i++) {
				if (strMonth.toUpperCase() == strMonthArray[i].toUpperCase()) {
					intMonth = i+1;
					strMonth = strMonthArray[i];
					i = 12;
			   	}
			}
			if (isNaN(intMonth)) {
				err = 3;
				return false;
			}
		}
		intYear = parseInt(strYear, 10);
		if (isNaN(intYear)) {
			err = 4;
			return false;
		}
		if (intMonth>12 || intMonth<1) {
			err = 5;
			return false;
		}
		if ((intMonth == 1 || intMonth == 3 || intMonth == 5 || intMonth == 7 || intMonth == 8 || intMonth == 10 || intMonth == 12) && (intday > 31 || intday < 1)) {
			err = 6;
			return false;
		}
		if ((intMonth == 4 || intMonth == 6 || intMonth == 9 || intMonth == 11) && (intday > 30 || intday < 1)) {
			err = 7;
			return false;
		}
		if (intMonth == 2) {
			if (intday < 1) {
				err = 8;
				return false;
			}
			if (LeapYear(intYear) == true) {
				if (intday > 29) {
					err = 9;
					return false;
				}
			} else {
					if (intday > 28) {
						err = 10;
						return false;
				    }
			   }
			}
			return true;
	}

	function LeapYear(intYear) {
		if (intYear % 100 == 0) {
			if (intYear % 400 == 0) { 
				return true; 
			}
		} else {
			if ((intYear % 4) == 0) { 
				return true; 
			}
		}
		return false;
	}
//  End -->
